Dinarchus, also spelled Deinarchus ( born c. 360 BC, Corinth [Greece]—died after 292 ) professional speech writer at Athens whose work is generally thought to reflect the incipient decline of Attic oratory. As a metic, or resident alien, he could not participate directly in the political life of Athens.

Dinarchus came to prominence in the scandal that followed the flight to Athens in 324 BC of Alexander the Great’s treasurer, Harpalus, who brought with him considerable wealth derived from the spoils of Alexander’s conquest of Asia. Dinarchus wrote the prosecution speeches against Demosthenes and other well-known politicians accused of misappropriating some of this money, and the three extant works generally ascribed to him are all concerned with these trials. The works are “Against Demosthenes,” “Against Aristogiton,” and “Against Philocles.” In 307 BC Dinarchus was exiled to Chalcis, an island near Attica. He returned to Athens 15 years later.

Dionysius of Halicarnassus records the titles of 87 speeches ascribed to Dinarchus, 60 of which he considered genuine. Dionysius’ Dionysius’s low opinion of the orator is supported, in the extant speeches, by the lack of creative skill, use of violent abuse in place of reasoned judgment, and plagiarism from other orators. Dinarchus was the last of the Alexandrian canon, or official list, of the 10 Attic orators.